JP2015089963A - Method for concentrating rhodium and ruthenium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for concentrating rhodium and ruthenium capable of concentrating rhodium and ruthenium at a low cost and with high efficiency without leaching rhodium and ruthenium.SOLUTION: There is provided a method for concentrating rhodium and ruthenium which comprises: a step of alkali-leaching selenium and tellurium by adding an alkali to a leached residue containing selenium, tellurium, rhodium and ruthenium to blow air; a step of solid-liquid separating a solution after the alkali-leaching step to obtain an alkali-leached residue containing a solution after alkali-leaching containing selenium and tellurium and rhodium and ruthenium; and a step of repeating a part of the alkali-leached residue to the alkali-leaching step.

Description

  TECHNICAL FIELD The present invention relates to a method for concentrating rhodium and ruthenium, and more specifically, rhodium suitable for concentrating rhodium and ruthenium in an alkaline leaching residue containing selenium, tellurium, rhodium and ruthenium obtained by wet treatment of a copper electrolytic product. And a method for concentrating ruthenium.

  In the electrolytic refining of copper, the crude copper from the converter is refined to about 99.5% in the refining furnace, and the cast anode (anode) and the seed plate or stainless steel plate as the cathode are alternately placed in the electrolytic cell. Hang in one set. Copper electrodeposited on a seed plate or stainless steel plate is called electrolytic copper. Impurities contained in the anode deposit in a muddy state at the bottom of the electrolytic cell. This deposit is called copper electrolytic deposit (anode slime). In the copper electrolyte, various precious metals in the raw material including gold are concentrated in addition to copper, and are used as a main raw material for precious metal recovery.

  In the treatment of copper electrolytic deposits, both dry methods and wet methods have been put into practical use, but it has been considered that the wet method is highly useful in terms of equipment cost, treatment flow, etc. . In the wet method, after the copper electrolytic deposit is pretreated through a copper removal step, a chlorination leaching step, and a gold extraction step, white metal is reduced using sulfurous acid gas to obtain a white metal-containing reduced product, and further, sulfurous acid. A reducing residue containing selenium and tellurium is obtained using gas.

  Since the reduction residue containing selenium and tellurium contains rhodium and ruthenium in addition to selenium and tellurium, a process of transporting the reduction residue to a treatment facility and recovering rhodium and ruthenium is performed.

  However, since the quality of rhodium and ruthenium in this reduction residue is not so high, as a pretreatment for recovering rhodium and ruthenium, impurities selenium and tellurium are further leached from the reduction residue, and rhodium and ruthenium are contained in the leaching residue. It is desirable to concentrate it.

  For example, Japanese Patent Application Laid-Open No. 2005-126800 discloses a method for concentrating rhodium and ruthenium contained in a reducing slag containing selenium and tellurium by repulping the reduction residue containing selenium and tellurium into sodium hydroxide and adding a certain amount of excess. A method of oxidizing and leaching selenium and tellurium has been proposed by a method in which hydrogen oxide is continuously added.

  In JP 2007-270233 A, a residue containing rhodium and ruthenium is mixed with an aqueous solution in which the number of moles of sodium hydroxide is 2 to 5 times the total number of moles of selenium and tellurium. A method of blowing is proposed.

JP 2005-126800 A JP 2007-270233 A

  However, the method described in Patent Document 1 has a problem that the chemical cost of hydrogen peroxide increases. Furthermore, even if leaching is completed at a constant oxidation-reduction potential, the reaction until the oxidation reaction stops due to the effect of hydrogen peroxide remaining in the aqueous solution is not constant, so the leaching reaction proceeds too much and leaching of ruthenium or rhodium. There is a problem that will let you.

  In the method described in Patent Document 2, by blowing air instead of hydrogen peroxide to oxidize and leach out selenium and tellurium, the chemical cost is lower than that in Patent Document 1, and the reaction can proceed more stably. However, there is still room for improvement in view of processing efficiency.

  In view of the above problems, the present invention provides a method for concentrating rhodium and ruthenium that can efficiently concentrate rhodium and ruthenium without leaching out rhodium and ruthenium.

  In order to solve the above-mentioned problems, the present inventors diligently studied. As a result, an alkali leaching residue and an alkali leaching solution were obtained by alkali leaching a residue containing selenium, tellurium, rhodium and ruthenium (alkali leaching step), In the treatment method of obtaining a sulfuric acid leaching residue and a solution after sulfuric acid leaching by leaching the obtained leaching residue with sulfuric acid (sulfuric acid leaching step), an alkali leaching residue obtained by the alkali leaching step and / or the sulfuric acid leaching step and / or It has been found that rhodium and ruthenium can be efficiently concentrated at low cost by repeating a part of the sulfuric acid leaching residue in the alkaline leaching step.

  The present invention completed on the basis of the above knowledge is, in one aspect, an alkali leaching step of adding alkali to a leaching residue containing selenium, tellurium, rhodium and ruthenium, and leaching the selenium and tellurium by alkali blowing, and an alkali The solution after the leaching step is subjected to solid-liquid separation to obtain a solution after alkali leaching containing selenium and tellurium and a solid-liquid separating step to obtain an alkali leaching residue containing rhodium and ruthenium, and a part of the alkali leaching residue is repeated to the alkali leaching step. This is a method for concentrating rhodium and ruthenium.

  In another aspect of the present invention, an alkali leaching step of alkali leaching selenium and tellurium by adding alkali to a leaching residue containing selenium, tellurium, rhodium and ruthenium and blowing air, and a solution after the alkali leaching step A solid-liquid separation, a first solid-liquid separation step to obtain an alkali leaching solution containing selenium and tellurium and an alkali leaching residue containing rhodium and ruthenium, and an acid is added to the alkali leaching residue and contained in the alkali leaching residue An acid leaching step for leaching selenium, a second solid-liquid separation step for solid-liquid separation of the solution after the acid leaching step, and obtaining an acid leaching solution containing selenium and an acid leaching residue containing rhodium and ruthenium; A method for concentrating rhodium and ruthenium comprising repeating part of the acid leaching residue to an alkali leaching step.

  In another embodiment, the method for concentrating rhodium and ruthenium according to the present invention includes repeating 20 to 70% by mass of the acid leaching residue to the alkali leaching step.

  In yet another embodiment, the method for concentrating rhodium and ruthenium according to the present invention includes repeating 20 to 70% by mass of the alkali leaching residue to the alkali leaching step.

  In yet another embodiment of the method for concentrating rhodium and ruthenium according to the present invention, the alkali leaching step is performed by blowing air while adding 50 to 150 g / L of caustic soda at a pulp concentration of 50 to 150 g / L. Adjusting the oxidation-reduction potential of -150 to -240 mV.

  In yet another embodiment of the method for concentrating rhodium and ruthenium according to the present invention, the acid leaching step is carried out at 70 to 90 ° C. while adding 30 to 80 g / L sulfuric acid at a pulp concentration of 100 to 150 g / L. Including stirring for more than an hour.

  ADVANTAGE OF THE INVENTION According to this invention, the rhodium and the ruthenium concentration method which can concentrate rhodium and ruthenium efficiently cheaply and without leaching rhodium and ruthenium can be provided.

It is a processing flow figure showing the concentration method of rhodium and ruthenium which concerns on the 1st Embodiment of this invention. It is a processing flow figure showing the concentration method of rhodium and ruthenium which concerns on the 2nd Embodiment of this invention.

<Residue to be treated>
Details of the present invention will be described below. The residue to be treated by the method for concentrating rhodium and ruthenium according to the present invention is a residue containing at least selenium, tellurium, rhodium and ruthenium.

  This residue is typically a residue containing selenium, tellurium, rhodium, and ruthenium obtained in a wet processing step of a copper electrolytic product. More specifically, it is possible to use the alkaline leaching residue after alkali leaching of tellurium-reduced soot after performing copper removal leaching, chloride leaching, gold extraction, and selenium reduction treatment with copper caustic soda. is there.

  The reduction residue contains 50 to 80% by mass of selenium, 10 to 40% by mass of tellurium, 0.05 to 0.25% by mass of rhodium, and 0.5 to 2.5% by mass of ruthenium. In the present invention, two embodiments for treating this residue and concentrating rhodium and ruthenium are described below.

(First embodiment)
As shown in FIG. 1, the rhodium and ruthenium concentration method according to the first embodiment includes an alkali leaching step, a first solid-liquid separation step, a residue repeating step after the first solid-liquid separation step, and an acid leaching. A process and a second solid-liquid separation process.

  In the alkaline leaching step, the residue containing selenium, tellurium, rhodium and ruthenium is 50 to 150 g / L, more preferably 70 to 100 g / L at a pulp concentration of 50 to 150 g / L, more preferably 80 to 100 g / L. Repulping into an alkaline aqueous solution such as caustic soda, and blowing the air while heating the solution to 70 to 90 ° C., more preferably 75 to 85 ° C., allows selenium and tellurium to be leached into the solution. In order to efficiently leach selenium and tellurium, the blowing of air is stopped at an oxidation-reduction potential (silver-silver chloride standard) of the solution of −150 to −240 mV, more preferably −180 to −220 mV, and the alkali leaching reaction is performed. It is preferable to stop.

  Next, the aqueous solution after the alkali leaching step is subjected to solid-liquid separation to obtain an alkali leached solution containing selenium and tellurium and an alkali leaching residue containing rhodium and ruthenium. The solid-liquid separation method is not particularly limited, but for example, a solid-liquid separation method using a filter press or the like can be used.

  The alkali leaching residue obtained in the first solid-liquid separation step contains selenium and tellurium as impurities in addition to rhodium and ruthenium to be recovered. In order to increase the content of rhodium and ruthenium in the residue finally obtained, a part of the alkali leaching residue is repeated to the alkali leaching step.

  The amount of the alkali leaching residue repeated to the alkali leaching step is preferably 20% or more of the total mass of the alkali leaching residue obtained by the alkali leaching reaction. Although the total amount of the obtained alkali leaching residue may be repeated in the alkali leaching step, the treatment time may be increased by repeating the entire amount of the alkali leaching residue in the alkali leaching process, and the processing efficiency may not be improved. In consideration of the amount of residue (acid leaching residue) to be recovered as a subsequent raw material for recovering rhodium and ruthenium, the repetition amount is more preferably 20 to 70% with respect to the total mass of the alkali leaching residue obtained. Is 20 to 50%, more preferably about 1/3 (33%).

  Next, acid is added to the alkali leaching residue obtained by solid-liquid separation, and the mixture is stirred at 70 to 90 ° C. for 8 hours or more while adding 30 to 80 g / L acid at a pulp concentration of 100 to 150 g / L, and alkali leaching. The selenium in the residue is further leached. As the acid, sulfuric acid can be used.

  The aqueous solution after acid leaching is subjected to solid-liquid separation by a filter press or the like to obtain an acid leaching residue containing rhodium and ruthenium and a solution after acid leaching containing selenium. The obtained acid leaching residue is sent to a rhodium and ruthenium recovery step as a raw material residue for recovering rhodium and ruthenium.

  According to the rhodium and ruthenium concentration method according to the first embodiment, rhodium and ruthenium are leached by repeating a part (for example, 1/3) of the alkali leaching residue after solid-liquid separation to the alkali leaching step. Therefore, it is possible to concentrate rhodium and ruthenium efficiently at low cost.

(Second Embodiment)
As shown in FIG. 2, the rhodium and ruthenium concentration method according to the second embodiment includes an alkali leaching step, a first solid-liquid separation step, an acid leaching step, a second solid-liquid separation step, and a second The step of repeating a part of the acid leaching residue obtained in the solid-liquid separation step to the alkali leaching step is included. In particular, the second embodiment is different from the first embodiment in that the acid leaching residue is repeated in the alkali leaching step.

  The acid leaching residue obtained after the second solid-liquid separation still contains selenium and tellurium as impurities in addition to rhodium and ruthenium to be recovered. By repeating a part of the acid leaching residue to the alkali leaching step, impurities such as selenium and tellurium can be further leached. Compared to

  The amount of the acid leaching residue repeated to the alkali leaching step is preferably 20% or more of the total mass of the acid leaching residue obtained by the acid leaching reaction. Although the total amount of the acid leaching residue may be repeated in the alkali leaching step, the processing time may not be improved by repeating the entire amount of the acid leaching residue in the alkali leaching process. In consideration of the amount of residue (acid leaching residue in FIG. 2) that is finally obtained as a raw material for collecting rhodium and ruthenium, the repetition amount is 20 with respect to the total mass of the alkali leaching residue obtained. It is preferable to set it to -70%, More preferably, it is 20-50%, More preferably, it is about 1/3 (33%). The other steps (alkali leaching step, first solid-liquid separation step, acid leaching step, second solid-liquid separation step) are substantially the same as those in the first embodiment, and therefore redundant description is omitted. .

  The alkali leaching residue obtained after the first solid-liquid separation step is sticky, and it may be difficult to separate a part of the residue for repeated use. On the other hand, the acid leaching residue obtained after the second solid-liquid separation step has a lower viscosity than the alkali leaching residue obtained after the first solid-liquid separation step, is easy to handle by the operator, and the impurities are acid leached. In addition, since the amount of generated residue is also reduced, it is possible to further improve the work efficiency compared to the first embodiment. Further, by repeating a part of the acid leaching residue obtained in the second solid-liquid separation step to the alkali leaching step, impurities (selenium, tellurium) in the residue are further removed, so rhodium in the ruthenium recovery raw material It is possible to increase the concentration of ruthenium. Although not shown in FIG. 2, in the second embodiment, a part of the alkali leaching residue obtained in the first solid-liquid separation step may be further repeated in the alkali leaching residue step. Of course.

  Note that the acid leaching residue that is partially repeated in the alkali leaching step in the second embodiment is not limited to the acid leaching residue obtained after the second solid-liquid separation step in FIG. 2, but selenium, tellurium, It may be an acid leaching residue derived from another process containing rhodium and ruthenium. For example, any acid leaching residue containing 10 to 65% by mass of selenium, 5 to 30% by mass of tellurium, 1 to 3% by mass of rhodium, and 10 to 25% by mass of ruthenium can be used in the present invention.

  EXAMPLES Examples of the present invention will be described below, but these are provided for better understanding of the present invention and are not intended to limit the present invention.

Example 1
As shown in Table 1, the pulp concentration of caustic soda and water is 25% by weight of alkaline leaching residue derived from copper electrolytic residue containing 21% by weight of selenium, 13% by weight of tellurium, 1% by weight of rhodium and 13% by weight of ruthenium. Repulping was carried out after adjusting to 80 g / L and caustic soda concentration of 90 g / L. After heating this aqueous solution to 80 degreeC, air was blown in with stirring and the alkali leaching process was started. When the redox potential on the basis of silver-silver chloride reached -200 mV, the blowing of air was stopped to terminate the reaction, and this was filtered with a filter press to obtain an alkaline leaching residue and a liquid after leaching.

  1/3 of the total weight of the obtained alkaline leaching residue was extracted and mixed with the raw material, and the second alkaline leaching treatment was performed under the same conditions as described above, and the oxidation-reduction potential based on silver-silver chloride was- At 200 mV, air blowing was stopped to terminate the reaction, and this was subjected to solid-liquid separation by a filter press to obtain an alkaline leaching residue and a liquid after leaching. Tables 2 and 3 show the composition of each component of the alkaline leaching residue obtained by solid-liquid separation and the liquid after leaching.

  As shown in Tables 1 to 3, it is possible to transfer selenium and tellurium into the solution after leaching without leaching Rh and Ru by further carrying out alkali leaching by repeating a part of the alkali leaching residue. It can be seen that rhodium and ruthenium can be efficiently concentrated. However, the alkali leaching residue repeated in the alkali leaching step in Example 1 was sticky, and it was difficult to separate a predetermined amount for repetition.

(Example 2)
1/3 of the total weight of the acid leaching residue shown in Table 5 is mixed with the alkali leaching residue shown in Table 4, and adjusted to a pulp concentration of 80 g / L and a caustic soda concentration of 90 g / L with 25% by mass of caustic soda and water. did. After heating this aqueous solution to 80 degreeC, air was blown in with stirring and the alkali leaching process was started. When the redox potential on the basis of silver-silver chloride reached -200 mV, the blowing of air was stopped to terminate the reaction, and this was filtered with a filter press to obtain an alkaline leaching residue and a liquid after leaching. Tables 6 and 7 show the composition of each component of the obtained alkali leaching residue and the liquid after leaching.

  By mixing the acid leaching residue and the alkali leaching residue and further performing alkali leaching, selenium can be leached into the solution after leaching without leaching Rh and Ru, and rhodium and ruthenium are efficiently concentrated. I was able to.

Claims (6)

An alkali leaching step of adding alkali to a leaching residue containing selenium, tellurium, rhodium and ruthenium, and leaching the selenium and tellurium by alkali by blowing air; and
Solid-liquid separation of the solution after the alkali leaching step to obtain an alkali leaching residue containing rhodium and ruthenium after the alkali leaching solution containing selenium and tellurium; and
A method for concentrating rhodium and ruthenium, comprising repeating a part of the alkali leaching residue to the alkali leaching step. An alkali leaching step of alkali leaching selenium and tellurium by adding alkali to a leaching residue containing selenium, tellurium, rhodium and ruthenium and blowing air;
A first solid-liquid separation step of solid-liquid separation of the solution after the alkali leaching step to obtain an alkali leaching solution containing selenium and tellurium and an alkali leaching residue containing rhodium and ruthenium;
An acid leaching step of adding an acid to the alkali leaching residue and leaching selenium contained in the alkali leaching residue;
The solution after the acid leaching step is solid-liquid separated to obtain a solution after acid leaching containing selenium and an acid leaching residue containing rhodium and ruthenium, and alkali leaching a part of the acid leaching residue A method for concentrating rhodium and ruthenium, comprising repeating the steps.   The method for concentrating rhodium and ruthenium according to claim 2, comprising repeating 20 to 70% by mass of the acid leaching residue to the alkali leaching step.   The method for concentrating rhodium and ruthenium according to any one of claims 1 to 3, comprising repeating 20 to 70 mass% of the alkali leaching residue to the alkali leaching step.   The alkali leaching step includes adjusting the redox potential in the liquid to a range of −150 to −240 mV by blowing air while adding 50 to 150 g / L of caustic soda at a pulp concentration of 50 to 150 g / L. The method for concentrating rhodium and ruthenium according to any one of claims 1 to 4.   The acid leaching step includes stirring at 70 to 90 ° C for 8 hours or more while adding 30 to 80 g / L sulfuric acid at a pulp concentration of 100 to 150 g / L. Method for concentrating rhodium and ruthenium.

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